Pathogens that can cause primary infections include viruses, bacteria, parasites, and fungi. These pathogens lead to different symptoms, types of health conditions, and treatments.
This article discusses the pathogens that lead to primary infections, including examples such as sexually transmitted illnesses (STIs). It will help you to know more about why specific infections occur.
Causes of Primary Infection
A primary infection occurs when you are initially exposed to a pathogen. For example, genital herpes occurs when you are exposed to the herpes simplex virus, even though infection persists in the body.
There are four different types of pathogens that can lead to a primary infection:
Viruses: These enter the body and spread to other cells, and can be mild like the common cold, or life-threatening, such as HIV or hepatitis-C. Fungi (singular: fungus): Yeast, mold, and mushrooms can cause allergic reactions and related illnesses. They’re difficult to eliminate once they’ve entered the body, and often the treatment, which may include antibiotics or antifungal medications, can have detrimental effects on the body as well. Ringworm and vaginal yeast infections are examples of fungal infections. Bacteria: While they can lead to primary infections, bacteria tend to be secondary infections, which enter the body after it’s been weakened by a virus. Strep throat and botulism are examples of bacterial infections. Parasites: These enter a host body and drain energy from the host. Tapeworm, which wreaks havoc on the digestive system, and Lyme-carrying are two examples of parasites that can make people sick.
Virus Infections
Viruses are pathogens that lead to an array of illnesses, from the common cold to COVID-19. The viral microorganisms can affect your respiratory system, digestive tract, neurological function and more.
Common illnesses caused by a virus also include:
Some types of bronchitis Stomach flu (gastroenteritis) Respiratory syncytial virus (RSV) Mononucleosis (related to the Epstein-Barr virus)
Some viral infections, like influenza, are easily spread but comparatively mild though they may cause serious illness or even death in some people. Good hygiene practices may limit their spread. Some viruses also may be prevented with vaccines.
Other viruses may lead to severe and often fatal illness, as is the case with Ebola virus and human immunodeficiency virus (HIV) that are not properly treated.
Treatment for a viral infection may be as simple as taking over-the-counter medication for symptom relief until the infection clears. Antiviral drugs, like those used to treat Hepatitis C infections, may be prescribed. In cases that require hospitalization, you may need:
IV fluids, electrolytes, or blood transfusions Supplemental oxygen and/or ventilator support Kidney dialysis
Fungal Infections
A fungal infection, formally called mycosis, is caused by a fungus. Fungi are a type of organism that lives in the environment—air, soil, and water—as well as in human and animal bodies. In some cases, the illnesses they cause can be contagious and spread.
Common fungal infections include:
Yeast infections (for example, affecting the mouth or vagina) Aspergillosis, a type of lung infection Meningitis, caused by infection with Cryptococcus neoformans
Many fungal infections affect the skin, as with athlete’s foot or ringworm, and are treated with antifungal medication. Others pose a deadly threat.
In October 2022, the World Health Organization identified 19 fungal pathogens that are a priority for researchers. This is because of increasing resistance to antifungal medications, and because more people appear to be affected by fungal infections. That’s especially true for people living with:
Chronic obstructive pulmonary disease (COPD)Liver diseaseChronic kidney disease
Secondary Infections
It’s important to note that the phrase “secondary infection” does not refer to the second time a person becomes infected with the same illness. Secondary infection is a different infection altogether, which can thrive in a person who has a primary infection.
Sometimes called “opportunistic infections,” secondary infections in HIV patients are able to do more damage because HIV weakens the immune system. Many patients who do not have HIV can fight off other viral and fungal infections that are potentially life-threatening to HIV patients.
